Al-Qaeda’s central leadership broke Monday with the Islamic State of Iraq and Greater Syria (ISIS), who in defiance of its orders joined Syria’s fighting, fueling bitter infighting among militant opposition factions in the civil war.

The break, announced in a statement Monday, appeared to be an attempt by the terror network’s leader, Ayman al-Zawahri, to establish control over the feuding militant groups in Syria and stem the increasingly bloody reprisals among them.

It also reflected a move by Zawahri, who succeeded Osama bin Laden as the group’s leader, to re-establish Al-Qaeda’s eminence in the jihadi movement in general, at a time when new militant groups have mushroomed not only Syria but around the region, inspired by Al-Qaeda’s ideology but not linked to it by organization.

The announcement sharpens a dispute raging the past year between Al-Qaeda’s central leadership and ISIS, which spread into Syria in early 2013, led by the head of Al-Qaeda’s branch in Iraq, Abu Bakr al-Baghdadi. He formed the group to expand his operations into neighboring Syria in defiance of direct orders by Zawahri not to do so and to stick to operations within Iraq.

Now, the break is likely to spark a competition for resources and fighters between the two sides in what has become a civil war within a civil war as Syria’s rebels fight against President Bashar Assad. The test for Zawahri’s influence will be whether his decision leads to fighters quitting ISIS.

In a conflict that has seen atrocities by all sides, ISIS has been particularly vicious.

It is believed to be dominated by thousands of non-Syrian jihadi fighters, seen by others in the rebellion as more concerned with venting sectarian hatred and creating a transnational Islamic caliphate than with toppling Assad.

Since its creation, it has taken over swaths of territory in northern and eastern Syria, often imposing Shariah law penalties harsher than other Islamic-minded groups.

Its fighters have beheaded captured government fighters, carried out some of the deadliest massacres against members of the pro-Assad Shiite and Alawite minorities and kidnapped anti-Assad activists, journalists and civilians seen as critical of its rule.

It has increasingly clashed with other factions, particularly an umbrella group of Syrian rebels called the Islamic Front, which accuses it of trying to hijack the campaign to oust Assad. Even the group’s name, Islamic State of Iraq and Greater Syria, was seen as a declaration that it was the only real Islamic movement in the country.

Those frictions erupted into outright warfare in January. Since Jan. 3, around 2,300 people have been killed in fighting between ISIS and other factions, according to the London-based Syrian Observatory for Human Rights. ISIS Saturday killed two senior commanders from factions that make up the Islamic Front, one of them in a giant suicide bombing that killed more than two dozen people near the northern city of Aleppo.

Also on the ascendant in his homeland Iraq, where ISIS has sought to present itself as the voice of that country’s Sunni minority against the Shiite-led government, Baghdadi is a powerful force in the jihadi movement.

Rival Islamic factions in Syria accuse him of trying to take over their movement in that country.

In Monday’s statement, Al-Qaeda’s general command announced that it has “no connection” with ISIS, underlined that the group “is not a branch of the Al-Qaeda organization,” and said Al-Qaeda “is not responsible for its actions.”

Al-Qaeda did not condone the group’s creation “and in fact ordered it to stop,” the statement said.

It also condemned the infighting among Islamic groups, saying, “We distance ourselves from the sedition taking place among the mujahedeen factions [in Syria] and of the forbidden bloodshed by any faction.” It warned that mujahedeen, or holy warriors, must recognize the “enormity of the catastrophe” caused by “this sedition.”

The authenticity of the statement could not independently be verified but it was posted on websites commonly used by Al-Qaeda.

Capt. Islam Alloush, a military spokesman for the Islamic Front, said Al-Qaeda’s announcement came late but praised it for isolating ISIS.

“This faction is without cover or co-sponsor. It has been totally stripped after Al-Qaeda and the people abandoned it,” Alloush told the Associated Press.